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• Dec. 12, 2003| 6 p.m. ETSee how cities grow: Some urban areas grow like vines, with urban tendrils radiating outward from a central hub. Others are like shrubs, gradually building up bigger edges and filling in empty pockets. Still others are like strawberries, with new clusters cropping up at some distance from the urban core.

The various patterns of growth pose different challenges for urban planners: Where should new water and sewer systems go? Which areas should get bigger roads? How should resources be used to support new housing and new schools? Using satellite imagery, Boston University researcher Annemarie Schneider has developed a new tool that graphically reveals trends in urban growth.

The method combines population density data with spectral readings from the Terra satellite’s MODIS spectroradiometer, which can distinguish between vegetation and developed areas. Schneider also used imagery from Landsat and the Pentagon’s Nighttime Lights project.

When all those data sets are put through a computer, the result is a false-color display showing how urban areas expand over time. During this week’s meeting of the American Geophysical Society, Schneider presented a survey of 30 midsized cities around the world, from Atlanta to Brasilia to Chengdu. Some of the urban areas, in Africa for instance, haven’t been mapped for years.

Annemarie Schneider
/
NASA Landsat

False-color image shows how the Chinese city of Chengdu changed during the 1990s. Urban land in 1990 is shown in yellow. Urban growth from 1990 to 2000 is shown in orange.

“These maps will not only be useful to scientists studying energy transfer, hydrology and climate interactions, but to social scientists trying to understand the land impacts of population and economic activity at a global scale,” Schneider said in a NASA report on the research.

For example, the analysis shows that cities in China and India exhibited the same kind of cluster growth pattern that has been fairly common — and fairly challenging — in the United States. The urban areas around Atlanta and Calgary grew 25 percent in a decade. Brasilia, on the other hand, showed only minimal growth in pockets over a similar time period.

“This is the first time actual data have been used to confirm theories made by urban researchers during the last century,” NASA reported.

For more on Schneider’s research, check out her Web site at Boston University. And don’t miss our slide show of cool Earth imagery, based on the Library of Congress’
Earth as art exhibit. Are there other ways satellites can shed light on society? If you come up with any bright ideas, share them with the Log.

• Dec. 12, 2003| 6 p.m. ETFeedback Friday: Stargazer/photographer Wally Pacholka, known for his pictures of
celestial shows
, sends along word of new honors coming his way: “One of my Mars images will be featured in Time’s Pictures of the Year issue. .... It will be a two-page spread. Life’s Pictures of Year issue comes out in February and will include another Mars image of mine, again a two-page spread noting the closest encounter of Earth and Mars in over 50,000 years.”

Meanwhile, maverick geophysicist J. Marvin Herndon — whose theories helped fuel the
plot of “The Core,”
a magnetic-storm disaster movie — sends along a link to a Current Biography article about him. Strangely enough, this week’s American Geophysical Union meeting brought fresh research into the prospects of a
magnetic pole flip
, which also plays a part in “The Core.”

Other feedback from this week focused on rumors that the White House might make more of a push for missions aimed at an eventual return to the moon. Here’s a selection:

Robert Wilton Dale: “Did I wake up this morning in a different dimension? An alternate reality? Are they actually talking of going back to the moon? Can I walk out of my house and head to the Space Port and grab a tourist ticket? Not yet, huh? Well, actually I’m just glad they’re talking — Bravo! I’ll pinch myself anyway ... Ouch! I love it!”

Wade Whitlock, Aberdeen, Md.: “What is the chance that the U.S. will return to leading us into space? Let’s see: We have a twit in the White House whose closest approach to heroic action has been eating a big sandwich. We’re overrun with MBAs who can’t see past today’s profit. We’re up to our armpits with lawyers, particularly in Congress, who haven’t got enough science and math credits among them to graduate with a B.S. (or at the very least talk, think and act as though they don’t). Our work ethic seems to be going, going ... and last but not least the people who should be leading the way (Yeah, the crew at NASA) seem to be losing sight of everything that made Mercury, Gemini and Apollo rock and roll. Just look at the ISS!

“Ah, I believe I understand, now. It will be a very cold day in Rio before we see the space elevator, L-anything, a permanent Tranquility Base, or a Mars base, either. ...”

Yvan Cartwright, Britain:“Am I right in thinking that a moon base for launching spacecraft on a voyage to Mars is backwards thinking? Although the moon is a lot closer than Mars is to us here, from a rocketry point of view it would take more fuel to get to the moon and then Mars than for a craft to head there directly. Now I’m all for testing various components of a Mars program out in lunar orbit first, but the cost of setting up a moon base before anything is launched Marswards is going to make any government balk. Test the Mars components in lunar orbit, then initiate a series of two-yearly launches (using the Mars Direct reference mission or a variant thereof) and then maybe go for a moon base if it supports a number of goals (scientific, exploratory, etc.). If it isn’t required yet, don’t build it. Mars Direct would cost something in the region of $50 billion over 10 years. Five billion dollars a year for the start of a new branch of human civilisation sounds cheap to me. Now if that sounds blunt then maybe that’s because I live in the U.K., and aside from a rather nifty rover landing in three weeks (hopefully), our interplanetary effort is almost nil (sadly).”

Still other correspondents had big questions about Professor Don Olson’s theory that “The Scream,” Edvard Munch’s masterpiece, was inspired by the eerie skies that followed the 1883 Krakatoa volcanic eruption:

Professor R. Davis, Brigham Young University at Rexburg, Idaho: “Don Olsen might be 110 percent correct about Krakatoa, but still 110 percent incorrect about Munch. It’s all guesses, no more, so while we’re pondering the possibilities we could add lots of others, too. Too many times, far too many times, I’ve seen our world doing it’s best to second-guess history, and too many times we’ve been far from the mark. Not an ounce of truth but great e-mail blather.”

Jess Vermont, Chicago: “Have the scientists ever contemplated the idea that perhaps the artists in question have an imagination and aren’t beholden to the world as it appears around them? Maybe Munch simply felt that the colors he chose for the sky were more expressive of the overall feeling he wanted to convey? A shame some people cannot just attribute these great works to the incredible power of the human imagination. In either case it adds nothing to the power of the images themselves.”

Anonymous: “I’m a painter. Orange is the expected color you would find with blue. Do these people have nothing better to do with their time than this?”

• Dec. 11, 2003 | 8:45 p.m. ETCelebrating flight:Festivities marking the centennial of flight reach takeoff speed on Friday at the Wright Brothers National Memorial in North Carolina. Tens of thousands are expected to turn out at the place where the Wrights flew 100 years ago, and NASA says the international space station’s astronauts are due to join the party via a video downlink from 10:04 to 10:24 a.m. ET.

The theme of Friday’s program is “Igniting the Imagination,” with a special focus on inspiring kids to follow in the footsteps of the Wright brothers in science and engineering.

“The invention of flight was a great milestone, and the celebration of its birth is an opportune time for NASA to reach out to the next generation of explorers,” said Adena Williams Loston, NASA’s associate administrator for education. Five days of music and memorializing lead up to the big re-enactment of the first flight next Wednesday.

Meanwhile, the Smithsonian’s National Air and Space Museum
dedicated
its new Udvar-Hazy Center today, with Vice President Dick Cheney in attendance. NASA Watch’s Keith Cowing reports that Cheney dropped no hints about the Bush administration’s future policy on spaceflight, but he also hears that the policy change is shaping up as “substantive and worth the wait.”

Like many others, Cowing was wowed by the Udvar-Hazy Center, which he called “America’s air and space cathedral.” It opens to the public on Monday.

A century of flightSpaceShipOne’s designer, Burt Rutan, was among the aviation pioneers honored during the dedication — and from the SpaceShipOne test site in California’s Mojave Desert, his team confirmed reports that the experimental craft’s rocket engine was tested during a flight last week. But the data log indicates that the engine was not actually fired up; rather, the pilot performed a “full functional check of the propulsion system by cold flowing nitrous oxide.”

“All propulsion components, displays and functionality performed as designed,” the team reported.

Now NASA’s Ames Research Center sends along the news that its own educational CD-ROM on flight, called Exploring Aeronautics, will be licensed as part of a commercial product called AeroCD.

You can also find out how the Wright Flyer replica was put to the test in NASA’s wind tunnels. If it surprises you that NASA has such a big role in the past and future of flight, it shouldn’t. Just give a thought to what the first “A” in NASA stands for.

• Dec. 11, 2003 | 8:45 p.m. ETSpace history in action: Experts at the Kansas Cosmosphere and Space Center are restoring the Gemini 6 spacecraft used in 1965 by Wally Schirra and Tom Stafford — and you can watch their progress over the Web. In cooperation with CollectSpace, the Cosmosphere is providing a Webcam view of the capsule as it undergoes refurbishment, supplemented by an illustrated journal.

• Dec. 10, 2003 | 8:45 p.m. ETCosmic holiday goodies: With just 14 more shopping days before Christmas, it’s high time to break out the Yule Log: If you look on the Web and in the skies, you’ll find plenty of celestial diversions to make the season bright.

For example, solar scientist Paal Brekke passes along a lighthearted look at “Rudolph on the Sun.” With a little help, you can pick out the dark outline of Santa’s favorite reindeer on the sun’s disk, as seen by the Solar and Heliospheric Observatory’s Extreme Ultraviolet Imaging Telescope.

“Of course, what we are really perceiving in the darker area (when viewed in extreme ultraviolet light) is a substantial coronal hole, a part of the sun where solar particles are following open magnetic field lines out into space,” said Brekke, the European Space Agency’s deputy project scientist for SOHO. “Like sunspots, they do not stay the same, bur rather develop and change over time.”

As Dec. 25 approaches, you’ll be able to track Santa’s progress using the NORAD Santa Web site. For 45 years, the North American Air Defense Command, or NORAD, has lent its name to Santa-monitoring exercises, and this year the site features some “declassified” views of the estimable Mr. Claus from the past four decades.

A guide to viewing meteor showersOn Saturday night, you just might catch a celestial Christmas-light display when the annual Geminid meteor shower reaches its peak. This year's display won't be as impressive as it could be, however, due to a gibbous moon that will wash out the night sky.

Look forward to hearing more about the Geminids and their curious history on Friday.

Christmas Night will bring another heavenly treat, when a crescent moon and the planet Venus hang out together in the skies of sunset. Science@NASA provides a preview, complete with a sky chart and schmaltzy yuletide verse. It’s fitting that Venus gets a star turn on Dec. 25, since some astronomers believe it could have played a “starring” role in the
world’s first Christmas
.

• Dec. 10, 2003 | 8:45 p.m. ETBetter odds for aliens? Three new studies fuel speculation that other Earths and perhaps extraterrestrial life may be more common than once thought.

The BBC reports on two of the studies from the Monthly Notices of the Royal Astronomical Society. One paper, written by Max Wallis and Chandra Wickramasinghe of Cardiff University, contends that microbes could survive being blasted into space by an asteroid or comet impact. The other, by Bill Napier of Armagh Observatory, says microbe-laden space debris could be pushed out of our solar system by the pressure of sunlight. That leads him to propose that our cosmic home is surrounded by an expanding “biosphere” of rocky fragments that contain dormant microbes — and that life could make the jump from one planetary system to another.

The third study, accepted for publication in the journal Icarus, says there could be a surprising number of planets out there capable of supporting life. The paper was written by Sean Raymond and Thomas Quinn of the University of Washington, along with Jonathan Lunine of the University of Arizona.

The astronomers ran 44 computer simulations of planet formation and said that each of those simulations produced one to four Earthlike planets, including 11 theoretically habitable planets as far away from their parent stars as Earth is from the sun.

“Our simulations show a tremendous variety of planets,” Raymond, a doctoral student, said in a University of Washington news release. “You can have planets that are half the size of Earth and are very dry, like Mars, or you can have planets like Earth, or you can have planets three times bigger than Earth, with perhaps 10 times more water.”

Do you think the hunt for new Earths will hit paydirt, or are we alone in the universe after all? For more on the search for distant planets, check out our “Other Worlds” interactive — then let me know what you think.

• Dec. 9, 2003 | 3 p.m. ETScience of ‘The Scream’: The researchers who tracked down where and when Vincent van Gogh painted a mysterious moonrise have turned their attention to another darkening sky: the eerie glow of “The Scream” by Edvard Munch, the famous Norwegian expressionist painter. What they found has shed light on the artist’s creative process as well as on atmospheric science.

It all started with a hunch that Munch was inspired by the vivid skies that followed the 1883 volcanic cataclysm on the Pacific island of Krakatoa. The eruption was so strong that it destroyed most of Krakatoa, now part of Indonesia, and set off huge tsunamis. Krakatoa’s blast could be heard thousands of miles away, and the fine dust that was spewed into the atmosphere caused blood-red sunsets and sunrises around the world for months.

Don Olson, the physics and astronomy professor at Texas State University at San Marcos who was involved in the earlier van Gogh mystery, said he was intrigued by a possible connection to the Munch masterpiece.

Munch Museum
/
Munch Ellingsen Group / ARS

Did Krakatoa inspire “The Scream”? Credit: National Gallery, Oslo / Copyright 2004 The Munch Museum / The Munch-Ellingsen Group / Artists Rights Society. Reproduction, including downloading of Edvard Munch’s works, is prohibited by copyright laws and international conventions without the express written permission of Artists Rights Society, New York.

“The sky in it looked like a Krakatoa twilight,” he said in the university’s report on the research. “I’m very familiar with the Krakatoa twilights, and my first reaction was, ‘That can’t be,’ because the first versions of ‘The Scream’ were painted in 1892 and 1893, and Krakatoa erupted in 1883.”

He and his research colleagues, Russell Doerscher and Marilynn Olson, searched the records for suitable volcanic eruptions that took place in the years just prior to 1892, but came up empty. Then they found out that some art historians had traced the inspiration for “The Scream” back to the 1880s — suggesting there might be something to the Krakatoa connection after all.

During a trip to Oslo, the scientists came up with what they called a “smoking gun” from Munch’s papers. Munch noted that “The Scream” and other works were based on rough sketches done in the mid-1880s, and that “these are illustrations of some memoirs from 1884.”

Norwegian records indicated that the Krakatoa glow started in November 1883 and lasted well into 1884. Armed with all that information, Olson and his colleagues matched up the sky conditions and the terrain of “The Scream” with southwest-facing vantage points on Oslo’s Ekeberg hill — one on the historic Ljabrochausséen road, and the other on a rocky ledge 420 feet above.

If the research team’s scenario is correct, Munch refined the moment over the course of eight years: The most famous rendition, immortalizing what the artist called his “great, infinite scream,” combined two geographical points of view with a Krakatoa sky. Such a case illustrates how artists put their raw emotions and experiences through rigorous and repeated processing in order to produce a masterpiece. Will future artists do the same with
Hubble's Hits?

• Dec. 8, 2003| 5 p.m. ET
Tracing the black-hole trail: The Chandra X-Ray Observatory has detected the telltale signs of an intergalactic collision that left myriads of black holes and neutron stars in its wake. You can see the evidence in the left-hand photo, which shows a trail of intense X-ray sources not apparent in the right-hand optical view.

The left photo shows Chandra’s X-ray view of galaxy NGC 4261. The right photo is the view from an optical telescope.

In a paper to be published in an upcoming issue of The Astrophysical Journal Letters, researchers from the Harvard-Smithsonian Center for Astrophysics say the X-ray pinpricks indicate that the galaxy NGC 4261 captured and pulled apart a smaller galaxy billions of years ago. That cataclysm would have led to the creation of many massive stars, and over time those stars collapsed into neutron stars and black holes. Some of the behemoths had companion stars, and as gas from those companions swirled into the gravitational whirlpools, energy was released in the form of X-rays.

Chandra was able to pick up that X-ray signature long after the optical evidence faded into the background of NGC 4261, the researchers say.

“This discovery shows that X-ray observations may be the best way to identify the ancient remains of mergers between galaxies,” co-author Lars Hernquist said in a news release that provides more background.

Several readers were intrigued by moonwalker Buzz Aldrin’s suggestion in The New York Times (registration required) that America should build a launch pad between Earth and the moon before it tries to establish a moonbase.

Mike: “The American space program needs a big push, and if competition with Chinese is the only way to make our government stand up, then so be it. We’ve had manned lunar landing technology for a very long time, and have done nothing with it since the Apollo missions. I personally believe that space should not be used for military means, though it seems that path is inevitable. Most of the world’s governments are so shortsighted in terms of human evolution that they can’t see beyond what they accomplished yesterday, and therefore can’t build a civilization for the future. Buzz Aldrin has a great idea with L1, but the governments of the world are likely to overlook it unless there is a military application. The privatization of space may well be exploration’s savior, but cost will ultimately be the deciding factor. Maybe Bill Gates should do something useful with his billions and invest in a privately funded space program. Maybe then I would purchase a copy of Windows.”

Rev. Carl R. Lott, Angola, Ind.: “Buzz Aldrin’s idea of a stable space platform at L1 is an idea that is past due. In the matter of a collision with a near-Earth object, the question is not if, but when. We have or will have the technology to address this inevitability. We ought to get cracking.”

Robert, Stevens Point, Wis.: “I agree that we should go back to the moon and forward to Mars. I find the timing of potentially announcing this goal rather interesting. They could have made this goal a long time ago, but instead they wait till China is looking to go to the moon? Of course, such a mission, despite our technology, is going to be expensive. Are they finally going to stop cutting NASA’s budget and give them the funding to do the mission right? We have been to the moon, and going back just to go back would be a very small move for us. I really do not think that would have the support of the American people as much as going to Mars would; however, if we go to the moon with the intention of setting up a lunar processing plant to provide cheap fuel to other destinations like Mars, then that makes going back worth it. Keep in mind the most expensive part of space exploration is the fuel to get us off our own planet. As soon as we have a lunar mining colony, the international space station will become a valuable resource. The ISS would be a perfect point to ship refined materials from the moon to as well as a refueling point for spaceships to go out to the moon, Mars and beyond. As far as the importance of the moon to us as a means of providing us a cheaper way to explore space, I would like to reference this Web site.”

Robert Wilton Dale, Tacna: “The United States should return to our moon with mining in the program. It would pay for itself and we could build our bases in the process — underground. We have the technology, why are we waiting? Until everyone else stakes their claim? Come on, we already have a flag up there. Let’s make a commitment now. I don’t like the idea of our children having to order ‘Kung Pao’ chicken up there.”

Chris Browne, Sarasota, Fla.: “I am very pro-space exploration, both human and robotic or remote; but I must say the idea of strip mining or using bombs to terraform the moon really bothers me. We’re talking about an object in frictionless space, the propinquity of which gives us tides and stability. Am I wrong, or might a hundred years of such activity result in a wobble? And might a wobbly moon have unforeseen — and perhaps devastating — consequences? Please let’s discuss this now before they start mining that green cheese.”

Robert, Denver: “There are a lot of advantages to setting up a permanent base on the moon. I believe that some of the initial construction should be accomplished by robotics. Sending humans to finish the job would be safer and cost much less. As far as Mars is concerned, I think we need another 20 years before we attempt that, based on our current knowledge of the planet and long-duration spaceflight.”

Rick Fialkowski, West Chester: “I think it’s about time that we get back to serious manned space exploration. I believe the space program took a wrong turn in the ’80s, focusing on low Earth orbit. The achievements that the ’60s program reached should have continued throughout the ’70s into the ’80s. If this was the case, we might be on our way to a manned mission to Mars or a nearby asteroid. ...”

Dennis McClain-Furmanski, New Haven, Conn.: “Too many presidents have made too many heroic sounding statements. Their actions speak louder. Heck, George Sr. said we’d go to Mars, but then made Dan Quayle head (luckily, figurehead) of the space program. When Congress passes the legislation and passes the appropriations, so that the money’s on its way to NASA’s account, then I’ll believe it. In the mean time, I’ll watch Rutan. He hasn’t lied yet.”

Anonymous: “Two words: space elevator. Do that first, then the rest will be much easier — and much more likely. OK, that was more than two words!”

• Dec. 8, 2003| 6:30 p.m. ETThe science of Santa: Just in time for the holidays, the folks who brought you the Ig Nobel Prizes have published new research on whether tiny tots really do have their eyes all aglow when they see Santa Claus.

According to the Annals of Improbable Research, Professor John Trinkaus of New York’s Zicklin School of Business was “surprised and saddened” to find that kids nowadays aren’t all that thrilled by the Jolly Old Elf, based on an analysis of facial expressions displayed by 300 children who came within sight of Santas at two New York-area shopping malls.

“Only 1 percent of them smiled or showed other signs of happiness,” Alice Shirrell Kaswell writes in AIR’s report on the research. “On the other hand, Professor Trinkaus noted, nearly all of the parents were visibly quite happy and excited.”